Loop-cut won't go all the way around
This is because the bottom face doesn't have the proper geometry, the edge ring tool doesn't know where to direct the ring since there are several vertices (it is an ngon). You can only use this tool on quads (4 sided faces). So to fix, you can use the knife tool and rework the ngon into a large quad.



Additionally, there is also another problem, you have duplicate vertices at the point where the cut stops. To fix, first box select (B) the points shown below and use Alt + M > At Center to merge the duplicate points into one.



After you do that, use the Knife Tool (K) to create a quad as shown below. Press K and select one vertex then another and press Enter. Repeat for the other side and you should be able to add edge rings after.